This adds some details to the image cache page in the admin docs about
how image cache disk usage is (not) considered in the scheduler disk
space calculation. Workarounds and mitigation strategies are provided.
Basically this patch is now a partial backport of
829ccbe2bb squashed into
57702ad484 .
Change-Id: I7f40f167cea073a73cf249a9adfd73e1187c031b
Related-Bug: #1878024
(cherry picked from commit ab3fab0322)
(cherry picked from commit 57702ad484)
(cherry picked from commit 147f1c753a)
5429fd3d6e